1. Field of the Exemplary Embodiments
The exemplary embodiments disclose herein relate to substrate processing apparatus and, more particularly, to apparatus for automating alignment of a substrate processing apparatus.
2. Brief Description of Related Developments
The manufacture of semiconductors, flat panel displays, and similar articles typically involves transporting substrates between substrate locations or stations in a substrate processing apparatus. Transport apparatus governed by electronic control systems are typically used for this purpose. A processing apparatus may include various devices through which substrates are cycled during fabrication. Each device may have one or more associated substrate stations. These stations may, for example, be locations at which a transport apparatus places and removes substrates from the device. Due to the objectives of minimizing costs of fabrication facilities and maximizing substrate throughput, equipment is often tightly arranged. Therefore transport apparatus move substrates through narrow pathways to avoid obstructions. Moreover, the ever decreasing size of microstructures formed on substrates demands highly accurate placement of substrates at desired locations. Hence, the substrates are moved along trajectories that are precisely and accurately determined. Accordingly, it is desirable for a transport control system to operate using an accurate representation of system geometry. Substrate station coordinates are taught to the control system upon initial setup of the system and are re-taught following events that may alter system geometry, such as replacement of a component.
One conventional method of teaching is to maneuver the transport apparatus and visually align the apparatus with each station. This manual method introduces subjectivity into the alignment. Skilled technicians are required, and even so it is likely that no two technicians will align the system in precisely the same manner. The manual method is time consuming and causes valuable equipment to sit idle. It is therefore desirable to automate the teaching process to improve accuracy and repeatability and to reduce required down-time. It is also desirable to do so without using specialized targets or sensors that are specific to the alignment process.